The present invention relates generally to earthworking implements and more specifically to an improved releasable lock means for locking a boom on a frame.
Releasable lock means for preventing pivotal movement of a backhoe boom have been known for several years and examples of present day commercial releasable locks are disclosed in U.S. Pat. Nos. 3,811,582 and 3,921,835, both assigned to the assignee of the present invention. The first of these patents discloses a releasable lock for a backhoe unit that is supported on a frame which is pivotally supported on a base structure of a vehicle. The releasable lock is designed such that the boom is automatically locked to the frame when the boom is moved to a transport position and can be unlocked by manipulation of a unit fluid ram that pivots the material handling unit on the outer end of the boom.
The other of these patents also discloses a releasable lock in which a boom is automatically locked on a frame when the boom is moved to the transport position with a manual release mechanism allowing the operator to release the lock whenever movement of the boom is desired.
In both of these units, the boom and frame can be pivoted about the vertical pivot axis while the boom is locked on the frame. This arrangement is desirable because many times it becomes necessary to swing the boom even though the material handling unit is not being used for transferring materials.
While both units disclosed in the respective patents have been commercially successful, manufacturers are constantly striving to provide a simpler mechanism which can readily be incorporated into existing machinery without any major modifications thereof and at a reduced cost.